<template>
    <view>
        <!-- 试用自定义的搜索组件 -->
        <my-search @click = "gotoSearch"></my-search>
        <view class="scroll-view-container">
            <!-- 左侧滑动区域 -->
            <scroll-view class="left-scroll-view" scroll-y="true" :style="{height: wh + 'px'}">
                <block v-for="(item,i) in cateList" :key="i">
                    <view :class="['left-scroll-view-item',i === active ? 'active' : '']" @click="activeChanged(i)">{{item.cat_name}}</view>
                </block>   
            </scroll-view>
            <!-- 右侧滑动区域 -->
            <scroll-view scroll-y="true" :style="{height: wh + 'px'}" :scroll-top="scrollTop">
                <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
                    <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
                    <view class="cate-lv3-list">
                          <!-- 三级分类 Item 项 -->
                          <view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
                            <!-- 图片 -->
                            <image :src="item3.cat_icon.replace('dev','web')"></image>
                            <!-- 文本 -->
                            <text>{{item3.cat_name}}</text>
                          </view>
                        </view>
                </view>
            </scroll-view>
        </view>
    </view>
</template>

<script>
    import badgeMix from '../../mixins/tabbar-badge.js'
    export default {
        mixins:[badgeMix],
        data() {
            return {
                // 当前设备可用高度
                wh:0,
                active:0,
                cateList:[],
                cateLevel2: [],
                scrollTop: 0
            };
        },
        onLoad() {
            const sysInfo = uni.getSystemInfoSync()
            // 可用高度 = 屏幕高度 - navigationBar高度 - tabBar高度 - 自定义的search组件高度
            this.wh = sysInfo.windowHeight - 50
            this.getCateList()
        },
        methods:{
            async getCateList(){
                const {data : res} = await uni.$http.get('/api/public/v1/categories')
                if(res.meta.status !== 200) return uni.$showMsg()
                this.cateList = res.message
                // 为二级分类赋值
                  this.cateLevel2 = res.message[0].children
            },
            activeChanged(i){
                this.active = i
                 // 为二级分类列表重新赋值
                  this.cateLevel2 = this.cateList[i].children
                    // 让 scrollTop 的值在 0 与 1 之间切换
                    this.scrollTop = this.scrollTop === 0 ? 1 : 0
                  
                    // 可以简化为如下的代码：
                    // this.scrollTop = this.scrollTop ? 0 : 1
            },
            // 点击三级分类项跳转到商品列表页面
            gotoGoodsList(item3) {
              uni.navigateTo({
                url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
              })
            },
            gotoSearch(){
                uni.navigateTo({
                    url:"/subpkg/search/search"
                })
            }
        }
    }
</script>

<style lang="scss">
.scroll-view-container{
    display: flex;
    .left-scroll-view{
        width: 120px;
        .left-scroll-view-item{
            background-color: #f7f7f7;
            line-height: 60px;
            text-align: center;
            font-size: 12px;
            &.active{
                background-color: #ffffff;
                position: relative;
                &::before{
                    content: ' ';
                    display: block;
                    width: 3px;
                    height: 30px;
                    background-color: #c00000;
                    position: absolute;
                    top: 50%;
                    transform: translateY(-50%);
                    left: 0;
                }
            }
        }
    }
    .cate-lv2-title {
      font-size: 12px;
      font-weight: bold;
      text-align: center;
      padding: 15px 0;
    }
    .cate-lv3-list {
      display: flex;
      flex-wrap: wrap;
    
      .cate-lv3-item {
        width: 33.33%;
        margin-bottom: 10px;
        display: flex;
        flex-direction: column;
        align-items: center;
    
        image {
          width: 60px;
          height: 60px;
        }
    
        text {
          font-size: 12px;
        }
      }
    }
}
</style>
